Zachary Cruz was killed Feb. 27 at the corner of Derby and Warring streets. The boy, a kindergartner at LeConte Elementary School, was headed toward UC Berkeley's Clark Kerr Campus for an after-school program.

Zachary's parents, Frank Cruz, a graduate student at UC Berkeley, and Jodie Cruz, filed their suit in Alameda County Superior Court in Oakland.

Named as defendants are truck driver John William Martin Sr.; his employer, Ferguson Welding Service in Hayward; the Berkeley Unified School District; school-bus driver Zakiya Green; after-school program employee Zayda Arevalo; and the University of California regents.

The suit said Green dropped Zachary off at Piedmont Avenue and Derby Street after Arevalo, who was walking several other children, waved at the bus. The location was not a designated school bus stop, the suit said.

As Arevalo crossed the street with Zachary and the other children, Martin's truck hit Zachary, the suit said.

The defendants have not responded to the suit in court.

Martin was not cited in the crash, which police ruled an accident.

E-mail Henry K. Lee at hlee@sfchronicle.com.